Drawbench



A. D. GETTIG oct. 19, 1943.

l DRAWBENGH 2 Sheets-Sheet 1 I I u KN Qs INVENTOR Alle D ATTORNEY 2 sheets'l-snet' 2 I Ill l L..

A. cals;1"rn::-

DRAWBENCH Filed Oct. 5. 1942 Oct. 19, 1943;

IN'VENToR B///en D. GdI/ ATTORNEY Patented oef i9, 1943 y UNITED vs'm'rlzs 1' A'i1=.1\1'r OFFICE DRAWBENCH Allen D. Gettig, New Kensington, Pa., assignor to Aluminum Company of America, Pittsburgh, l Pa., a corporation of PennsylvaniaV Application October 5, 1942, Serial No. 460,747

Fig. 5 is a longitudinal sectional view on an 7Claims.

, This invention relates to drawbenches, and it aims to provide a guard structure which is simvple in form and reliable in operation, and so disposed with respect to the pass line and the draw chain as to prevent contact between the. work or tube and the draw chain, particularly in connection with the use of automatic gripping tongs in which the grip' on the tube is released and the tube ejected from the tongs when the tube is drawn completely through the die or drawing tension is otherwise suddenly relieved as by Another object of the invention is to provide an4 eective lightweight guard structure which will enable higher draw speeds to be employed and which will render the drawbench safer to operate than in drawbenches equipped with various types of carriage operated guard mechanism as heretofore employed. A further object of the invention is to provide a guard device that is'secured to the tongs carriage and extends therefrom in enlal'zged scale of a portion of the structure of Fig. i

5 Fig. 6 is a view taken on the line VI-VI of Fig.

: and

Figs. 7 and 8 are plan and side views, vrespectively, of the guard structure which is attached to the tongs carriage.

In the drawbench illustrated, referring to Figs. 1 and 2, the structure includes a mandrel section 3, a die section t, and a draw section 5. The mandrel section and the draw section are of considerable length as is well known, each being long enough to accommodate the desired lengths of tubes to be operated upon. The mandrel section may consist of a suitable framework, here shown as comprising a pair of laterally spaced channels 6 suitably supported along their lengths on upright supports or stands l. At one end the. channels maybe supported 'on a stand 8, and at the other end, they may be secured to a die carrying frame or support 9. The die support 9 includes a die holder I0 in which is remova plane belowthe die pass line together with means for effecting return movement of the carriage and guard to starting position without buckling of the elongated guard device. Still another object of the invention-,is to provide a drawbench and guard construction of generally simplified and improved form.

Other objects and advantages of the invenv tion will become apparent from the detail description of thev invention taken in commotion with the accompanying drawings illustrating a preferred embodiment of the invention, wherein:

Fig. 1 is a plan view of the drawbench;

Fig. 2 is a side elevational view thereof partly in section;

Fig. 3 is a diagrammatic view illustrating the in the usual way.

ably mounted a die Il throughwhich the tube I2 is drawny The tube I2 is inserted upon a mandrel rod I3 in the. usual manner and has its one end pointed for threading through the die II. The mandrel. as here shown, is carried by a transversely reciprocable gear housing Il, two

mandrels being employed so that during a drawfy ing operation, a tube may be threaded onto the other mandrel while it is out of alignment with the die.` When the drawing of the tube from the one mandrel is completed, the housing I 4 may be shifted to bring the loaded mandrel into alignment with the. die. Shifting of the housing I4 is eil'ected by manipulation of a rocking lever I5 Each mandrel rod carries a bulb I6 (Fig. 5) which cooperateswith the die to control the wall thickness ofthe tube. The position of the bulb I6 4with respect to the die is controlled by4 operation of vhand cranks Il, a crank being provided for each mandrel and having connection through the. linkage, as illustrated, with suitable adjusting mechanism in the housing Il for eifecting axial movement of the respective mandrels so as to locate the bulbs I6 thereon in the desired relationship with the die II. A ram I8 is actuated by longitudinal shifting of the lever I5 in order to force a loaded mandrel and its bulb forwardly into operating relationship with the die.

All of the foregoing partsfand structure are located above and to either side of the flanges of the respective channels 6, as will be apparent from I l an inspection of Fig. 4. Mounted along the inner tongs carriage 22, which carriage is provided with flanged wheels 23 for traveling movement along track bars 24 that are secured to the upper flanges of spaced channels 25 at the draw section 5 of the drawbench. These channels 25, like the channels 6, are supported on suitable intermediate pedestals or supports 26 and at their ends are secured to the die supporting framework 9 and a gear housing 21, respectively. At the start of the drawing operation, the carriage 22 is located adjacent the die I0, and the guard 2| extends rearwardly therefrom through the die supporting housing 9 (as best seen in Fig. 5) in a plane located downwardly with respect to the pass line or center of the die and it terminates at a point near the rear end of the channels 6. It will be appreciated that the guard device is of considerable length. In fact, it is of a length substantially equal to the maximum length of travel of the tongs carriage. most remote position with respect to the die the rear end of the guard 2| will be located rearwardly of the die supporting housing 9.

A draw chain 28 of any suitable construction is disposed between the channels 25 slightly below the level of the track bars 24. The chain passes around an idler sprocket wheel 29 adjacent the die Il) and it also passes around a driving sprocket 30 in the gear housing 21. The upper run of the chain is supported on suitable longitudinal supports which may take the form of a channel 3| (Figs. 5 and 6) that may be supported at spaced points throughout its length on a series of transversely extending bars 32 that are secured at their ends to the webs of the channels 25. 'I'he lower run of the chain is similarly supported on a longitudinally extending channel member 33 (Fig. 2). An idler sprocket 34 supports the return run of the chain as it passes onto the supporting channel 33.

With the carriage moved to its the die.

The sprocket 38 is mounted on a shaft 35 journailed in the housing 21. The shaft carries a gear 36 which meshes with and is driven by a pinion 31 formed on one end of a drive shaft 38. The shaft 38 may be driven in any suitable manner but as here shown it carries a series of pulleys 40 around which pass a plurality of V-belts 4|, which in turn pass over a series of pulleys 42 mounted on the end of the shaft of a motor 43. The motor` 43 may be supported on a bracket 44 pivotally carried by the housing 21 and having adjusting devices 45, as illustrated in Fig. 2, whereby the tension of the V-belts may be adjusted as desired. I

'I'he draw chain 28 is preferably continuously operated, and the carriage 22 is adapted to be operatively connected thereto by means of a chain hook 41, the hookbeing preferably mounted on the carriage so that it may be swung downwardly to engage the chain. Counterweights 48 normally maintain the hook in raised position. Any suitable means may be used tolower the hook. As here shown, an air cylinder operated bell crank lever 58 is arranged to lift one of the counterweights 48, thereby rocking the shaft to which the hook is` secured, and lowering the hook. The carriage also carries a pair of gripping jaws 49 (Fig. 5) that are disposed in inclined guideways for movement toward each other to grip the pointed end of the tube therebetween in a well known manner. The jaws are adapted to be actuated by means of rocking levers 50 connected thereto through links 5|, the upper ends of the levers 50 carrying cylinders 52. Each cylinder contains a piston 53 and springs 54 and 55 on the opposite sides of the piston. Each piston is connected through a rod 56 with respective legs of a Y-shaped arm 51 on the hook arm 41 as shown more clearly in Figs. 5 and 6.- It will be appreciated that through the connections just described the hook'arm is yleldably or resiliently connected with the tube grips so that when the hook is lowered into engagement with the chain, springs 54 will be compressed to rock the levers 50 and move the jaws 49 rearwardly, at which time they move toward each other and grip the point end of the tube therebetween. Of course, the gripping of the tube is effected before the hook actually engages the chain, the springs 54 allowing the hook t'o be lowered sufficiently to establish contact with the chain, whereupon the carriage moves forwardly with the chain to pull the tube through Preferably a switch 59 (Fig. 2) is actuated by the bell crank lever 58 upon lowering of the hook 41 thereby, to initiate the operation of electrical acceleration circuits for the motor 43, in a well known way, so as to effect the drawing operation at an increasing rate of draw head travel.

The tension or pull of the chain on the hook causes the hook immediately to swing upwardly to a position substantially as shown in Fig. 5 so that the pistons 53 are moved rearwardly to effect compression of the springs 55. The levers 50 are thus biased in a direction tending to move the jaws 49 to release the tube. The tube, consequently, will be released immediately upon passage of the tube through the die since the drawing tension is abruptly terminated, allowing the compressed springs 55 to be elective to retract the gripping blocks 49. It also happens that sometimes during the draw, rupture of the tube occurs and, of course, the ruptured end of the tube is immediately released from the jaws. In either event, the released tube falls and it would impinge against the chain 29. However, the guard 2| will receive the tube, it being moved forwardly along with the carriage.

As shown more clearly in Figs. 5, 7, and 8, the forward end of the guard is provided with a pair of lugs 60 which bear against shoulders 6| toward the front side of the carriage 22, stud bolts 63 serving to rigidly attach the lugs 60 to the carriage. Thus, during forward travel of the carriage, the guard structure also will be moved therewith and the tube or any portion of a tube when released will be received by the guard structure. Preferably the upper surface of the guard structure is located substantially level with or slightly above the upper surface of the track rails 24, whereby the tubes may be rolled across the guard and removed from the drawbench.

A series of rollers 64 similar to the rollers 20 are providedalong the inner sides of the channels 25 and also in the die supporting housing 9 in order to support the guard structure.

As shown more clearly in Figs. 7 and 8, the guard structure comprises two side rails 65 and transverse connecting rails 66. These rails constitute a skid frame, and cover sheets 61 are suitably secured to the upper side thereof either by riveting or by spot welding. The cover sheets 61 assaooe are disposed :i end to end relation and preferably abut each other so as to form a continuous or `unbroken supporting surface or platform. Due

to the continuity of the surface of the guard structure, it will be appreciated that it will be impossible for a, drawn tube or any short length of broken tube to come into contact with the chain 29, such as sometimes happens in those cases where longitudinally spaced swinging arms y and other types of guard devices actuated by movement of the carriage are relied upon to prevent engagement between the tube and the chain.

The present structure, therefore, affords positive' protection against the tube engagingthe chain, even though it is quite likely that the tube may be ejected forcibly and rapidly endwise from the slipping iaws.

vstructure would be quite likely to deflect in a vertical direction and move into contact with portions of the drawbench, This difficulty is completely overcome by applying a pulling force' to the guard structure whereby the force necessary to return the structure and the carriage places the guard under onsiderable tension and maintains it straight so that it moves readily along the upper sides of the supporting rollers and 64. This arrangement also makes it unneces- 'sary to provide an extremely stiff guard struc- The carriage 22 is adapted to be moved back to the die l0 by means of a returncable 69 which extends around an idler pulley or sheave 10 adjacent the housing 21 and around an idler sheave 1l near the rear end of the mandrel section. One end of the cable is suitably connected to the carriag'e 22, as indicated at l2 (Figs. 1 and 6), while its other end is connected to a clevis 'I3 that is secured to the rear end of the guard structure 2l. The cable leaves the pulley 1l and is trained around a pair of driving pulleys 14 and 'l5 and around a pair of pulleys 1S and l1. From the later pulley it extends forwardly and passes around the front pulley 18.

The reeving arrangement for the cable is shown more clearly in Fig. 3 wherein it will be seen that the cable runs from the front side of the pulley lil to the far side thereof and extends rearwardly and is looped about the upper idler pulley 16 from the front side to the back side thereof. From this point the cable is crossed over to the front side of the lower driving pulley l5 andI passes around the same to the far side thereof and crosses over to the front side of the lower idler pulley 11 and is trained therearound and leaves the far side of the pulley -11 and extends to the front end of the drawbench to the pulley 10. Thus, it will be seen that the cable is connected to the center of the guard at the clevis 13 and has sufficient wrap around the driving pulleys 14 and 'l5 to effectively drive the same. It also leaves the idler pulley 11 near one side of the drawbench so that it may easily be run forwardly to wrap around the pulley 'I0 and be joined to the carriage with minimum of interference .with other portions of the operating mechanism. The set of idler pulleys 16 and 11 are carried on a supporting bracket 'I8 (Figs. 1 and 2) 'which is supported on the undersides of the channels 6 for sliding movement therealong.

Adjusting screws 19 are provided whereby thev position of the pulleys I6-'I1 with respect to the driving pulleys 14-15 may be adjusted in order to tighten and maintain the cable in a taut condition. The pulleys ll-15 are adapted to be driven through a reduction unit 80 that is driven by a motor 8l through a suitable brake and coupling unit 82. 4

The connection of the cable to the rear end of the guard structure is an important feature of this invention for the reason that it enables a simple lightweight guard structure to be employed, thereby eliminating imposition of excessive weight and drag on the carriage 22 which would, if present, increase the load on the driving motor 43 and also on the draw head return motor 8l. In addition, the considerable length of the guard structure makes it very flexible in a verture which, if possible, would be Very involved and expensive.

In. a transverse guard, of course, is not very great and it, therefore, is sumciently resistant to deection so that no middle support therefor is necessary, and when a tube is loaded thereon, undue deflection will no t take place. The guard may be constructed of any suitable material, preferably soft metal such as aluminum being used for the cover sheet Si so as to provide a substantially soft surface, thereby to eliminate danger of scratching or marring the surfaces of highly finished tubing.

From the foregoing, it will be seen that there is provided a drawbench structure of substantially simplified form of but few operating parts wherein complete protection for the work is provided. It will be understood, of course, that various changes and modications may be made in the structural arrangement of the mechanism, equivalent elements maybe substituted for certain of the parts illustrated, and various other changes may be made without departing from the spirit of the invention or the scope of the appended claims.

What is claimed is:

l. In a drawbench, a die headand a die mounted therein, a draw head movable away from said die to eiect a drawing operation, a draw chain for moving said draw head in said direction, an elongated member secured to said draw head land extending rearwardly therefrom in a plane below theI pass line of said die, to receive the drawn article when it drops from said pass line, and means connected to said member for tensioning and moving the same and the associated drawing head in a direction opposite to that effected by said draw chain, whereby buckling of said elongated member s prevented during return movement thereof.

Y 2. In a drawbench, a die head and a die mounted therein, a draw head movable away from said die to effect a drawing operation,l a draw chain for moving said draw head in said direction, an yelongated member secured to said draw head and extending rearwardly therefrom in a plane below the pass line of said die to receive the drawn article when it drops from said pass line, and means connected to said member for tensioning and moving the same and the associated drawing head in a direction opposite to that effected by said draw chain, whereby buckling of said elongated member is prevented during return movement thereof, said member having a length substantially equal to lthe maximum length of travel of said draw head.y

3. In a draw bench. a die and bulb for a tube to be drawn, a draw chain, a carriage initially direction, the width of the positioned adjacent said die and having a hook for engaging said chain whereby the carriage is moved away from said die, means on the carriage for gripping the end of a tube projecting through said die whereby the tube is drawn completely vthrough the die by said movement of said carriage, an elongated platform secured at one end to said carriage and extending yrearwardly therefrom, means for supporting said platform in a plane above the upper run of said chain, said platform forming a movable cover overlying said chain for receiving the drawn tube thereon when the tube is released from said die and said gripping means, and means for imparting traveling movement to said platform and said carriage in a direction to return the carriage to said initial position. u

4. In a draw bench, a die and bulb for a tube to be drawn, a draw chain, a carriage initially positioned adjacent said die and having a hook for engaging said chain whereby the carriage is moved away from said die, means on the carriage for gripping the end of a tube projecting through said die, whereby the tube is drawn completely through the die by said movement of said carriage, an elongated platform secured at one end to said carriage and extending rearwardly therefrom, means for supporting said platform in a movable along said trackway, a draw chain between the front side members with its upper run disposed below the level of said trackway, means on the carriage to detachably couple it to said chain, means on the carriage to releasably grip the end of a tube projecting through said die, an elongated guard device secured to said carriage for traveling movement therewith, said guard device extending rearwardly from said carriage in a plane below the pass line of said die and above said upper run of the draw chain and having a substantially continuous upper surface,

supporting means secured to the inner faces of plane above the upper run of said chain, said platform forming a movable cover overlying said chain for receiving the drawn tube thereon when the tube is released from said die and said gripping means, a power actuated cable, and pulleys at opposite ends of the drawbench, one end of said cable being trained around the pulley at the front end of the bench and being connected to said carriage, the other end of the cable being trained around the rear pulley and being connected to the rear end of said platform to pull it rearwardly and return said carriage to said initial position.

5. A drawbench comprising a die and bulb for a tube to be drawn, a front and a rear bench section each including a pair of laterally spaced side members, a die support between said bench sections, mechanism for supporting and manipulating said bulb and supported on said rear bench section, a trackway at the top of said side members of the front bench section, a tongs carriage said side members of the iront and rear bench sections for supporting said guard device at its marginal edges, and means for returning said carriage toward said die, said die support having a passageway for passage of said guard device therethrough.

6. 'I'he structure as deiined in claim 5 wherein said guard device is located substantially at the level of said trackway for discharge movement of the drawn tube thereacross.

7. In a drawbench, the combination with a die, a draw head comprising a carriage, a draw chain for moving the carriageto eiiect a drawing operation, and a cable for returning the carriage to the die, of a guard device movable longitudinally into covering relationship with said chain behind said carriage to receive drawn articles thereon, said devicel comprising a pair oi. side rails having a length substantially equal to the maximum length of travel of said carriage, cross rails connecting said side rails to form an elongated skid frame, a series of sheet members secured to the upper side of said skid frame in end to end relationship and forming a substantially continuous plane surface, an upstanding member on the upper side of said skid frame adjacent one end thereof for attachment to said carriage, a connecting element secured to the other end of said skid frame for attachment, of said return cable thereto, said guard device being moved alternately in opposite longitudinal directions by the pulling action of said carriage and said return cable, respectively, andaneans engaging said side rails for supporting said guard device in its longitudinal path of travel.

` ALLEN D. GETI'IG. 

